package com.shop.user.handler;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

/**
 * @author 'banxia'
 * @version 1.0
 * @description 生成订单表的全局ID
 * @date 2023/2/26 0:15
 */
@Component
public class CreateOrderIdHandler {

    @Autowired
    private StringRedisTemplate redisTemplate;


    /**
     * 开始时间戳：2022/1/1 0/0/0
     */
    private static final long BEGIN_TIMESTAMP = 1640995200L;
    /**
     * 序列号的位数
     */
    private static final int COUNT_BITS = 32;

    public long nextId() {
        // 1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowSecond - BEGIN_TIMESTAMP;

        // 2.生成序列号
        // 2.1.获取当前日期，精确到天
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        // 2.2.自增长
        long count = redisTemplate.opsForValue().increment("orderId:"  + date);

        // 3.拼接并返回
        return timestamp << COUNT_BITS | count;
    }

}
